Many studies have been made on regenerative medicine for regenerating cells, tissue, or organs damaged by diseases or accidents with artificial materials or cells. Normally, it is known that a body has a self-protective function, and when foreign matter such as a thorn enters a shallow position in the body, the body tries to force the foreign matter out of the body, while when foreign matter enters a deep position in the body, fibroblasts aggregate around the foreign matter, and a capsule of connective tissue mainly composed of fibroblasts and collagen is formed to cover the foreign matter, thereby isolating the foreign matter in the body. A plurality of methods are reported in which using the latter self-protective reaction, tubular tissue derived from a living body with living cells in a living body is formed (see Patent Literatures 1 to 3).
Patent Literature 4 discloses a stent in which, for example, a mesh-like tubular biocompatible stent body of metal is entirely covered with a connective tissue layer, and an artificial valve is formed integrally with the connective tissue layer. The stent is covered with a connective tissue film formed in a living body, and the tissue film is rich in matrix such as collagen, thereby allowing vascular endothelium to be rapidly organized and reconstructed.